This description of related art is provided for the purpose of generally presenting a context for the disclosure that follows. Unless indicated otherwise herein, concepts described in this section are not prior art to this disclosure and are not admitted to be prior art by inclusion herein.
Many computing and electronic devices include a transceiver to facilitate communication over a wireless network or directly with other devices. To increase the available capacity of wireless bandwidth, additional bands of spectrum have been allocated for wireless access networks. To use these additional bands, transceivers are designed to have oscillator circuits that cover an increasingly wider frequency range in an RF circuit, such as a voltage-controlled oscillator (VCO).
Covering the wide frequency range of cellular radio bands can involve using multiple voltage-controlled oscillators (VCOs), which consume a large amount of power and die area of an integrated circuit. Solutions to widen the turning range of a single VCO can lead to a degradation of phase noise or an increase in power consumption by the VCO, as well as occupying an even larger area on an integrated circuit.
Degeneration is one technique that is used to reduce phase noise, especially flicker or 1/f noise, in VCOs. Degeneration circuits or networks are circuit elements that are configured as a tuned circuit or circuits that reduce the generation of phase noise in a VCO. The degeneration network is tuned to the second harmonic of the VCO frequency to improve phase noise. In implementing wideband VCOs, the quality factor (Q) of degeneration networks may be reduced, lowering the effectiveness of the degeneration network to reduce phase noise in the output of the VCO.